MACHINE TOOL COOLANT FILTERING SYSTEM

Abstract: A machine tool coolant filtering system (10) is disclosed as including a plurality of coolants filter tanks (12a), (12b), (12c). Each filter tank (12) is designated for receiving coolant carrying a different material contaminant. A pipe network (20) and pipe branches (24) control communication of coolant to the coolant filter tanks (12). Liquid level within respective tanks (12a), (12b), (12c). Modulating valves (46) in communication with the liquid level sensors (40) control outflow from the respective tanks (12a), (12b), (12c). The coolant filtering system (10) segregates different material contaminants carried by common machine tool coolants for recycling.

Description: MACHINE TOOL COOLANT FILTERING SYSTEM Technical Field This invention relates to filtering apparatus for machine tool coolant, and more particular- ly, to a filtering system that accommodates a single machine tool for machining a variety of materials or a variety of machine tools for machining different materi¬ als whereby a common coolant is used in the system, the different filtered contaminants are segregated and a threshold range of coolant level throughout the system is maintained. Background Art Conventional machine tool coolant filter¬ ing systems include a dirty coolant tank having a filter medium, a clean coolant tank and pumping means for circulating the coolant. Although there is increased emphasis on recycling, conservation and waste disposal, conventional systems make no provision for segregating different material contaminants. In one typical arrangement, a plurality of machine tools are connected to such a filtering system. When one or more of the machine tools is being used to machine a stock of material that is different from that of a material being machined by other machines connected to the system, the chips or contaminants collected on the same filter are mixed. Likewise, in another arrangement where one machine is used to machine stock of different materials, the filter collects and mixes the chips or contaminants. In either arrangement, there is no provision for segregating different material chips or contaminants. Summary Of The Invention An object of the present invention is to provide a machine tool coolant filtering system that segregates different material contaminants carried by a common machine tool coolant. Another object of the invention is to provide a machine tool coolant filtering system that regulates and maintains a threshold coolant level among a plurality of filter tanks in the system. A more specific object of the invention is to provide a machine tool coolant filtering system including a plurality of coolant filter tanks having filter means for filtering machine tool coolant having different material contaminants from machine tools. Each filter tank is designated for receiving coolant carrying a different material contaminant. A pump moves coolant through the filter tanks and communicates the coolant from the machine tools to the coolant filter tanks. A liquid level sensing means mounted in each coolant filter tank senses coolant level within its respective tank and a respective modulating valve in communication with the sensing means regulates the coolant level in any of the respective tanks to maintain the coolant level within a threshold range in each coolant filter tank. Preferably, the system includes a clean coolant reservoir tank in communication with the coolant filter tanks. The clean coolant tank receives cleaned coolant from the filter tanks and supplies the cleaned coolant to the machine tools. In one preferred embodiment of the invention, the liquid level sensing means is a bubbler. in another embodiment, the liquid level sensing means is a pressure transducer. Other types of conventional liquid level sensors are within the scope of the inven¬ tion. The system also includes a diverter gate in cooperable operation with each machine tool to divert coolant having different material contaminant through a part of the coolant return network to the appropriate coolant filter tank. Most preferably, the system includes a liquid level controller in the reservoir for controlling and maintaining the volume of coolant in the reservoir tank. The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings. BriefDescription OfThe Drawings FIGURE 1 is a schematic view of a machine tool coolant filtering system for filtering machine tool coolant having different material contaminants con¬ structed in accordance with the present invention; FIGURE 2 is a continuation of the sche¬ matic view of FIG. 1; and FIGURE 3 is a schematic flow diagram illustrating the coolant flow of the filtering system of Figure 1. Best Mode For Carrying Out The Invention Referring to Figure 1 of the drawings, a machine tool coolant filtering system 10 constructed in accordance with the present invention is generally indicated by reference numeral 10. The machine tool coolant filtering system 10 is used for filtering machine tool coolant from machine tools 11 that are used to machine stocks of different materials and therefore have different material contaminants. As is hereinafter more fully described, the machine tool coolant filtering system 10 filters the machine tool coolant, separating the contaminants for recycling, and maintains a thresh¬ old coolant level range in each part of the system. As shown in Figure 1, the machine tool coolant filtering system 10 comprises a plurality of coolant filter tanks 12a, 12b, 12c, each having a filter assembly. Such filtering systems are described in detail in U.S. Patent No. 4,421,645 and U.S. Application Serial No. 481,646. The machine tool coolant filtering system 10 hereinafter described includes three filter tanks 12a, 12b and 12c, each being designated for receiving coolant carrying a different material contami¬ nant. For example, tank 12a receives coolant contami¬ nated with steel chips, etc.; tank 12b receives coolant contaminated with aluminum chips, etc. ; and tank 12c receives coolant contaminated with titanium chips, etc. Tanks 12b and 12c include a bubbler 14 for whetting floating chips. Each coolant filter tank 12 has a rotatable filter 16 that filters machine tool coolant contaminated with machining chips etc. from the machine tools 11. A suction conduit 18 communicates filtered coolant to a filter pump hereinafter described. A pipe or flume network 20 communicates coolant from a machine tool or machine tools 11 to and from filter tanks 12. A coolant communication control system 22, schematically represented, includes a plurality of pipe branches 24 communicating a working fluid, such as air or hydraulic fluid, for controlling the communi¬ cation of the machine tool coolant from the coolant filter tanks 12. Coolant control system 22 includes a vacuum sensing control 22a, a filter electrical control panel 22b, liquid level controls 22c, pressurized air supply 22d, current to pressure transducers 22e, and pneumatic solenoid valves 22f. A liquid level sensing means 40 is mounted in each of the coolant filter tanks 12 for sensing coolant level within its respective tank. The liquid level sensing means 40 illustrated in Figure 1 is a bubbler assembly including a level control bubbler probe 42 and a make-up bubbler probe 44. Both probes 42,44 are connected to deliver feedback to control system 22. Other types of sensing means 40 contemplated include a pressure transducer (not shown) which measures the fluid pressure as a function of depth for indicating coolant level in the tanks 12, conductive probes, ultrasonic instruments and others. A modulating valve 46 in communication with the control system 22 and the liquid level sensing means 40 in each filter tank 12 is controlled by the respective liquid level sensed by the respective probe 42,44. If the machine tool coolant level in a respec¬ tive tank 12 falls below a threshold range as indicated by the sensing means 40, the respective modulating valve 46 is closed to restrict coolant from being removed from its respective tank to maintain the coolant level in the respective tank. If the coolant level in any tank 12 rises above the threshold range, the respective modulat¬ ing valve 46 is opened to allow removal of machine tool coolant. This system maintains the coolant level within the threshold range in each filter coolant tank 12. With further reference to Figure l of the drawings, the machine tool coolant filtering system 10 also includes a common clean coolant reservoir tank 48 in communication with each of the coolant filter tanks 12 via suction conduit 18 and the machine tools 11 for receiving cleaned machine tool coolant from the filter tanks and resupplying the clean coolant to the machine tools. Tank 48 also includes a vacuum sensing stand pipe 48a and filter vacuum release valve 48b. Electri- cally driven vertical pump assemblies 50 provide the suction required to draw the coolant through the filters 16 and suction conduit 18, and to pump clean fluid to the machine tools. Diverter gates 52 shown schematically in Figure 1 segregate coolant having different material contaminants by diverting coolant and contaminant carried within the pipe or flume network through a part of the network designated for carrying certain contami¬ nants to the appropriate coolant filter tank 12. This diversion allows different material contaminants to be segregated and collected in a specified filter tank 12 which contaminant can thereafter be easily gathered for recycling. Figure 2 is a flow chart illustrating the operation of the modulating valves 46 in the machine tool coolant filtering system 10 which allows a common supply of coolant to be used to simultaneously carry different contaminants, filter the coolant in different filter tanks 12 and thereby segregate the contaminants for recycling. As illustrated by block 60, the machine tool coolant level in filter tanks 12a, 12b, 12c illustrated by blocks 62, 64 and 66, respectively, is continuously monitored. Blocks 68, 70 and 72 represent the suction valves on the suction side 16 of each of the respective filter tanks 12. If the coolant level in any of the tanks 62, 64, 66 is monitored as being low, i.e. falling below the threshold range, the respective suction valve is closed to restrict coolant from being removed from the respective tank to maintain the coolant level in the respective tank. If the machine tool coolant level in any of the respective tanks 12 is monitored as being above the threshold range, the respective suction valve 68, 70, 72 is opened to allow removal of the coolant in the tank to bring the level of coolant in the tank down within the threshold range. While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.

Claims: What Is Claimed Is: 1. A machine tool coolant filtering system for filtering machine tool coolant from at least one machine tool having different material contaminants, the filtering system comprising: a plurality of coolant filter tanks having filter means adapted to filter material contaminants from the at least one machine tool; each filter tank being designated for receiving coolant carrying a different material contaminant; each of said coolant filter tanks having a suction side adapted to be placed in fluid communication with a pump to have suction applied to the suction side; a fluid control communication system including a plurality of branches for controlling the communicat¬ ion of coolant from the at least one machine tool to said coolant filter tanks to selectively communicate contaminated tool coolant to respective designated filter tanks depending on the particular material contaminant carried by the tool coolant; a liquid level sensing means mounted in each coolant filter tank for sensing coolant level within its respective tank; and a modulating valve in communication with said liquid level sensing means at the suction side of each filter tank; each of such modulating valves being controlled by its respective liquid level sensing means whereby if the coolant level in its respective tank falls below a threshold range, the respective modulating valve is closed to restrict coolant being removed from its respective tank to maintain the coolant level in said respective tank and if the coolant level in said tank rises above the threshold range, the respective modulating valve is opened to allow removal of coolant, thus maintaining the coolant level within the threshold range in each coolant filter tank. 2. A system as in claim 1 further including a clean coolant reservoir tank in communication with said coolant filter tanks and the at least one machine tool for receiving cleaned coolant from said filter tanks and supplying the cleaned coolant to the at least one machine tool. 3. A system as in claim 1 wherein said liquid level sensing means is a bubbler. 4. A system as in claim 2 further comprising at least one pump in fluid communication with the suction side of said coolant filter tanks. 5. A system as in claim 2 further including a diverter gate in cooperable operation with each machine tool of the at least one machine tool for diverting coolant and contaminant through branches of said communication system to appropriate coolant filter tanks when different material contaminants originate from the same machine tool. 6. A machine tool coolant filtering and recycling system for filtering machine tool coolant from at least one machine tool having different material contaminants, and for segregating the contaminants for recycling, the system comprising: a plurality of coolant filter tanks having filter means adapted to filter material contaminants from the at least one machine tool; each filter tank being designated for receiving coolant carrying a different material contaminant whereby to segregate different types of contaminants; each of said coolant filter tanks having a suction side adapted to be placed in fluid communication with a pump to have suction applied to the suction side; a fluid control communication system including a plurality of branches for controlling the communicat¬ ion of coolant from the at least one machine tool to said coolant filter tanks to selectively communicate tool coolant to different designated filter tanks depending on the particular material contaminant carried by the tool coolant; a liquid level sensing means mounted in each coolant filter tank for sensing coolant level within its respective tank; and a modulating valve in communication with said liquid level sensing means at the suction side of each filter tank; each of such modulating valves being controlled by its respective liquid level sensing means whereby if the coolant level in its respective tank falls below a threshold range, the respective modulating valve is closed to restrict coolant being removed from its respective tank to maintain the coolant level in said respective tank and if the coolant level in said respective tank rises above the threshold range, the respective modulating valve is opened to allow removal of coolant, thus maintaining the coolant level within the threshold range in each coolant filter tank. 7. A system as in claim 6 further including a coolant reservoir tank in communication with said coolant filter tanks and the machine tools for receiving cleaned coolant from said filter tanks and supplying the cleaned coolant to the machine tools. 8. A machine tool and coolant filtering system for machining blocks of different materials and using a machine coolant to cool and lubricate the machine tool during machining, the system comprising: at least one machine tool for machining different materials; a plurality of coolant filter tanks having filter means adapted to filter material contaminants from the at least one machine tool; each filter tank being designated for receiving coolant carrying a different material contaminant; each of said coolant filter tanks having a suction side adapted to be placed in fluid communication with a pump to have suction applied to the suction side; a fluid control communication system including a plurality of branches for controlling the communicat¬ ion of coolant from the at least one machine tool to said coolant filter tanks to selectively communicate contaminated tool coolant to respective designated filter tanks depending on the particular material contaminant carried by the tool coolant; a liquid level sensing means mounted in each coolant filter tank for sensing coolant level within its respective tank; a modulating valve in communication with said liquid level sensing means at the suction side of each filter tank; each of such modulating valves being controlled by its respective liquid level sensing means whereby if the coolant level in its respective tank falls below a threshold range, the respective modulating valve is closed to restrict coolant being removed from its respective tank to maintain the coolant level in said respective tank and if the coolant level in said tank rises above the threshold range, the respective modulating valve is opened to allow removal of coolant, thus maintaining the coolant level within the threshold range in each coolant filter tank; at least one pump in fluid communication with the suction side of said coolant filter tank for apply¬ ing suction across the filter means and for circulating the coolant; and a clean coolant reservoir tank in communica¬ tion with said coolant filter tanks and the at least one machine tool for receiving cleaned coolant from said filter tanks and supplying cleaned coolant to the at least one machine tool; wherein the system is closed and uses a predetermined quantity of machine tool coolant which is recycled and the modulating valves maintaining the coolant level in the threshold range in the filter tanks. 9. The system of claim 7 wherein: the at least one machine tool includes a plurality of machine tools. 10. A method for filtering machine tool coolant from at least one machine tool having a plurali- ty of different material contaminants, the method comprising: identifying the particular contaminant in the machine tool coolant of each of the at least one machine tool; providing a plurality of coolant filter tanks having filter means adapted to filter material contami¬ nants from the at least one machine tool; each filter tank being designated for receiving coolant carrying one of the plurality of different material contaminants; collecting contaminated tool coolant from each of the at least one machine tool in a fluid control communication system fluidly connecting the at least one machine tool to the plurality of coolant filter tanks, the fluid control communication system having a diverter gate means for selectively placing the at least one machine tool in fluid communication with the coolant filter tanks; selectively positioning the diverter gate means to place the fluid control communication system in respective fluid communication between each of the at least one machine tool and each of the corresponding designated filter tanks so that the material contami¬ nants remain segregated from one another; filtering the identified contaminants from the contaminated tool coolant in the respective filter tanks to produce clean machine coolant; and pu ping the clean machine coolant back to the at least one machine tool for use in further machine tool operation; whereby the plurality of contaminants from the at least one machine tool remain segregated from one another. 11. The method of claim 10 wherein: the at least one machine tool includes at least two machine tools, the machine tools having at least two different material contaminants which are respectively filtered from machine tool coolant in at least two different designated coolant filter tanks. 12. The method of claim 10 wherein: the at least one machine tool includes only one machine tool, the one machine tool producing differ¬ ent material contaminants at different times; selectively positioning the diverter gate means at the different times so that each of the respec¬ tive contaminants and machine tool coolant are communi- cated to the respective designated coolant filter tanks so that the different contaminants remain segregated from one another. 13. The method of claim 10 wherein: each of the coolant filter tanks has a liquid level sensing means mounted in each coolant filter tank for sensing coolant level within its respective tank; and a modulating valve is provided in each respec¬ tive coolant filter tank allowing coolant to be with¬ drawn from the respective coolant filter tank; each liquid level sensing means communicating with the modulating valve in its respective tank; each of such modulating valves being con¬ trolled by its respective liquid level sensing means whereby if the coolant level in its respective tank falls below a threshold range, the respective modulating valve is closed to restrict coolant being removed from its respective tank to maintain the coolant level in said respective tank and if the coolant level in said respective tank rises above the threshold range, the respective modulating valve is opened to allow removal of coolant, thus maintaining the coolant level within the threshold range in each coolant filter tank.

Inventors: BAILEY MICHAEL R, MCEWEN SCOTT M, BAILEY, MICHAEL, R., MCEWEN, SCOTT, M.
Applicants: HENRY FILTERS INC, HENRY FILTERS, INC.
Application year: 1994
Main classification: B01D17
IPC codes: B01D17, B01D33, B01D35